Biological Invasions

, Volume 16, Issue 8, pp 1573–1579 | Cite as

Eurasian otters modify their trophic niche after the introduction of non-native prey in Mediterranean fresh waters

  • Rafael Barrientos
  • Raquel Merino-Aguirre
  • David H. Fletcher
  • David AlmeidaEmail author
Invasion note


Biological invasions are a major driver behind disturbances in freshwater community structure. We investigated how the foraging strategy of the Eurasian otter Lutra lutra (L.) has responded to this change in a Mediterranean catchment of the Iberian Peninsula, over a 30-year time span (1980 vs. 2010). We found that, despite continuing to feed on a considerable amount of native fish, this carnivore has adapted its trophic niche to accommodate non-native species. Prior to the massive introductions of these new food items (1980), otters diversified their diet during the limiting season (i.e. summer drought). However, otters had largely incorporated non-native prey into their diet in 2010, with red-swamp crayfish being their main food resource, especially in the summer. This increased crayfish consumption reflects a narrowing of trophic niche during the summer drought in 2010. We discuss how this heavy specialisation may compromise the conservation of otters and their endemic fish prey.


Diet Iberian Peninsula Invasive species Lutra lutra Red-swamp crayfish Spraint analysis 



R.B. received financial assistance from JCCM-FSE 2007/2013 postdoctoral program and from Juan de la Cierva program from the Spanish Ministry of Competitiveness. D.A. held a postdoctoral fellowship from JCCM-FSE 2009/2011 (PO 2007–13) through the University of Castilla-La Mancha (Spain).


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Rafael Barrientos
    • 1
  • Raquel Merino-Aguirre
    • 2
  • David H. Fletcher
    • 3
  • David Almeida
    • 1
    • 3
    Email author
  1. 1.Departamento de Ciencias Ambientales, Facultad de Medio AmbienteUniversidad de Castilla-La ManchaToledoSpain
  2. 2.Department of EcologyComplutense University of MadridMadridSpain
  3. 3.Centre for Conservation Ecology and Environmental ChangeBournemouth UniversityPooleUK

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